Runner for hydraulic machines having a center portion and an outer segmented portionsecured together to provide an assembled runner



F. SCHMIDT 2,784,936

PORTION OGETHEIR TO March 12, I957 RUNNER FOR HYDRAULIC MACHINES HAVING A CENTER AND AN OUTER SEGMENTED PORTION SECURED T PROVIDE AN ASSEMBLED RUNNER Filed May 2, 1955 Patented Mar. 12, 1957 RUNNER FOR HYDRAULIC MACHINES HAVING A CENTER PORTION AND AN OUTER SEG- MENTED PORTION SECURED TOGETHER TO PROVIDE AN ASSEMBLED RUNNER Franz Schmidt, Wauwatosa, Wis., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis.

Application May 2, 1955, Serial No. 505,217 2 Claims. (Cl. 253--117) This invention relates to hydraulic machines such as turbines, pumps and machines operable as either a turbine or a pump. More particularly this invention relates to a runner construction for such hydraulic machines, the runner being the element that is rotated by. water in a machine operating as a turbine and the runner being the element that is rotated by a motor to impel fluidin a machine operating as a pump.

Hydraulic turbines, pumps and reversible machines operable as either a turbine or a pump are being designed of larger Size than previous designs and it has become increasingly diflieult to manufacture the larger runners for such machines.

Foundries are often unable to cast a large runner because their facilities have inherent limitations as to the size of a casting that can be poured and handled.

It has been especially difficult to cast runners for large hydraulic machines because such runners may have spiral vanes that may be as much as 20 feet or more in length and if a large runner is cast in one piece cooling of the casting causes the vanes to shrink an amount often sufiicient to crack the casting. It is well known in this art that runners can be cast in several pieces which may then be bolted together to provide a completed runner. However, the constructions previously known in this art have not been satisfactory for runners of large sizes.

One such construction previously known to this art is to provide a vaneless center portion cast in a single piece and a number of segments each having a vane cast integrally therewith and have these segments bolted around the outer periphery of the center portion to provide a large runner. Although this construction did reduce the overall size of the castings the vanes were still cast in one piece and were still subjected to excessive shrinking relative to the segments with which they are integrally cast. Furthermore, in order to provide vanes with the radial length required in large machines, it became necessary to have the vanes project radially inward of the outer periphery of the center portion, and since the vane was not cast integrally with the center portion water impinging on the vane caused the vane to vibrate and flutter, reducing the eflicieney of the machine. The prior art proposed to reduce this fluttering vibration by securing single piece vanes to a hub portion, the vanes being secured to the hub along their entire length. This provided a more rigid structure and reduced the fluttering vibrations of the vanes and although vanes .werecast separately of the hub, the problem of reducing the size of castings was not completely solved because the diameter of the hub portion had to be large enough for the entire length of a vane to be secured thereto and so the original problem of casting the large piece then reappeared to plague the foundry.

The principal object of this invention is to provide a new and improved runner comprising several separately cast pieces assembled to form a runner of such size that would be ditficult to cast in one piece. To accomplish this object, one of the runner pieces provides a center portion for the runner and the remaining pieces form a segmented collarlike portion around the center portion. As in the usual type runner, the runner is provided with a plurality of vanes. According to this invention, however, each of the vanes is cast in two parts, one part being integrally cast with the center portion and the other part integrally cast with one of the segments of the col lar portion. Each of the two vane parts that are to form a single vane has a mutually coextensive edge arranged to abut the other and provide a single vane having a continuous surface extending from a hub portion of the center portion outwardly to the outer periphery of the collar portion.

Another object of this invention is to provide a new and improved runner having vanes constructed and arranged to reduce any tendency of the vane to flutter when impinged upon by a stream of water as occurs in a turbine. or when impelling a fluid as in a pump. According to this invention neither of the two parts of each vane ex-.

tends radially outward or inward a distance greater than the piece with which such vane part is integrally cast. Since no portion of either part of a vane projects cantilever fashion from the piece with which such vane part is integrally cast, the pieces and vane parts provide a more rigid runner structure less susceptible to fluttering than runners of construction heretofore known to this art.

Still another object of this invention is to provide a new and improved runner assembled from separately cast pieces which, when assembled, provide a runner of such size that would be diflicult to cast in one piece.

And still another object of this invention is to provide a new and improved runner made of several separately tween-the hub 11 cast pieces with improved means for securing the pieces together. I

Objects and advantages other than those above set forth will be apparent as the descri tion of the invention proceeds.

The novel features of the invention and how the objects are obtained will appear from the specification and the accompanying drawing showing an embodiment of the invention and forming a part of this application and all of these features are intended to be pointed out in the claims. a

lathe drawings:

Fig. 1 is a plan view of a runner for a hydraulic ma: chine embodying this invention; 1

Fig. 2 is a view taken in section along line Il-II in Fig. 1. a i

Referring to the drawing, a runner embodying the pres ent invention is shown as comprising a center portion 2 and an annular outer collar portion. is made up of several segments 4 arranged around the peripheryof the center portion 2. Each of the segments 4 is secured to an outer peripheral surface: of the center portion 2 by means of bolts 5, 6. Each of the segments 4 is also secured to the adjacent segments by means of bolts 7, 8. a p

The center portion 2 comprises an annular hub 11 (Fig. 2) and an annular shroud 12 spaced apart from each other. A plurality of vane parts 13 are disposed be:

shroud 12 and the vane parts 13 are integrallycast as a single piece. Each of the vane parts 13 extends outwardly from the hub 11 and terminates in an outer edge 14 that merges with an outer edge 15 and an outer edge 16 of the hub and shroud respectively.

Each of the segments 4 comprises a pair of shroud pieces 21, 22 spaced apart from each other. A second vane part 23 is disposed between the shroud pieces 21 and 22. Shroud pieces 21, 22 and the second vane parts 23 are integrally cast in a single piece. Each of the second vane parts 23 extends radially between an inner edge The outer portion and the shroud 12. The hub-11,

24 and an outer edge 25 of each shroud piece 21, 22, respectively. Each of the second vane parts 23 has an inner edge 26 between shroud pieces 21, 22 coextensive with an outer edge 14 of a first vane part 13. The segments 4 are arranged around the center portion 2 and bolted thereto with inner edge 26 of each second vane part 23 abutting outer edge 14 of each complementary first vane part 13 to provide a vane having continuous surfaces extending from the hub 11 to the outer periphery of the segments 4.

To insure the segments 4 being securely attached to the center portion 2 the hub 11 is provided with an annular ridge 30 projecting away from the center portion. Ridge 30 engages a complementary annular groove 31 in each shroud piece 21. The groove 31 is located in a portion of shroud piece 21 that extends radially inward from the outer edge 15 of hub 11. The bolts pass through the ridge 30 and groove 31. The complementary suriaces of annular ridge 30 and groove 31 are subjected to shearing stresses as a result of centrifugal force created by rotating the runner 1 that would be transmitted to bolts 5 if no interlocking surfaces such as the ridge and groove were provided.

Shroud 12 is provided with an annular shoulder 34 for engagement with a complementary annular ridge 35 formed on shroud piece 22. The bolts 6 are arranged to pass through the shoulder 34 and ridge 35. Thus shoulder 34 will carry some of the weight of segments 4 and reduce the stresses applied to the joint of annular ridge 30 and groove 31. Bolts 6 will hold segment-s 4 against shroud 1 2 and resist any tendency of centrifugal force to pivot the segments 4 counterclockwise around ridge 30. Thus shroud piece 21 is secured to hub 11 and shroud piece 22 is secured to shroud 12 in a manner that provides not only a strong assembly capable of withstanding stresses applied as the result of the weight of the segments 4 (especially when the runner is positioned with the axis of rotation in a vertical position) but also a structure strong enough to withstand stresses caused by the centrifugal forces set up by rotating the runner.

From the foregoing it will be apparent to those skilled in the art that the illustrated embodiment of the invention provides a new and improved runner for hydraulic machines and the like and accordingly accomplishes the objeots of the invention. On the other hand it will also be obvious to those skilled in the art that the illustrated embodiment of the invention may be variously changed and modified for features thereof embodied in other combinations than those illustrated without departing from the spirit of the invention or sacrificing all of the advantages thereof. Accordingly the disclosure herein is illustrative only and the invention is not limited thereto.

It is claimed and desired to secure by Letters Patent:

1. A runner for hydraulic machines comprising an integrally cast center portion having a circular periphery and an annular outer portion made up of a plurality of integrally cast segments arranged around the periphery of said center portion, and means for securing said segments to a periphery of said center portion to provide an assembled runner, said center portion comprising an annular hub and an annular shroud spaced apart from each other, a plurality of vanes between said hub and said shroud, each of said vanes extending from said hub outwardly and terminating in an outer edge merging with an outer edge of said hub and said annular shroud, and each of said segments of said outer portion being made up of a pair of shroud pieces spaced apart from each other and a vane between said shroud pieces, each of said vanes of said segments extend-ing between inner and outer edges of said shroud pieces, said vanes of said segments each having an inner edge between said pieces coextensive with an abutting said outer edge of a complementary vane of said center portion to provide an extension thereof outwardly .to the periphery of said annular outer portion, and said means for securing said segments to said center portion comprising an annular ridge formed in the periphery of said hub concentric to the central axis of said hub and projecting axially away from said center portion, an annular groove in the said shroud pi ce adjacent said hub, said ridge projecting into said groove, a plurality of bolts passing through said groove and into said ridge, an annular shoulder projecting radially of said center portion shroud, said shoulder projecting outwardly and overlapping an adjacent shroud piece, and a plurality of bolts passing through said shoulder and into said adjacent shroud piece to thereby secure said segments to said center portion.

2. A runner for hydraulic machines comprising an integrally cast center portion having a circular periphery and an annular outer portion made up of a plurality of integrally cast segments arranged around the periphery of said center portion, and means for securing said segments to a periphery of said center portion to provide an assernbied runner, said center portion comprising an annular hub and an annular shroud spaced apart from each other, a plurality of vanes between said hub and said shroud, each of said vanes extending from said hub outwardly and terminating in an outer edge merging with an outer edge of said hub and said annular shroud, and each of said segments of said outer portion being made up of a pair of shroud pieces spaced apart from each other and a vane between said shroud pieces, each of said vanes of said segments extending between inner and outer edges of said shroud pieces, said vanes of said segments each 7 having an inner edge between said pieces coextensive with an abutting said outer edge of a complementary vane of said center portion to provide an extension thereof outwardly to the periphery of said annular outer portion, and said means for securing said segments to said center portion comprising an annular ridge formed in the periphery of said hub concentric to the central axis of said hub and projecting axially away from said center portion, an annular groove in the said shroud piece adjacent said hub, said ridge projecting into said groove, an annular shoulder projecting radially of said center portion shroud, said shoulder projecting outwardly and overlapping an adjacent shroud piece, and means for securing said shoulder to said adjacent shroud piece to thereby secure said segments to said center portion.

References Cited in the file of this patent UNITED STATES PATENTS 705,347 Harris July 22, 1902 782,343 King Feb. 14, 1905 1,337,659 Kerr Apr. 20, 1920 1,849,557 Stelzer Mar. 15, 1932 2,401,206 Van Rijswijk May 28, 1946 FOREIGN PATENTS 333,336 Germany Feb. 21, 1921 

